(
Tumores cerebrales
)
Few things are more frightening than finding out your child has
a brain tumor. Yet it's a fear many parents have had to face.
Brain tumors are now the second most common group of childhood
cancers, after
leukemia
, affecting approximately 2,300 children each year.
Some can be cured relatively easily; others have a poorer
outlook. All require a very specialized treatment plan involving a
team of medical specialists, and all are likely to take a
tremendous physical and emotional toll on the kids and their
families.
What Is a Brain Tumor?
A tumor is any mass caused by abnormal or uncontrolled growth of
cells. Tumors in the brain are categorized according to several
factors, including where they're located, the type of cells
involved, and how quickly they're growing.
Medical terms doctors may use to describe brain tumors
include:
-
Primary vs. secondary:
Primary brain tumors originate in the brain. Secondary brain
tumors are made up of cells that have spread (metastasized) to
the brain from somewhere else in the body. In children, most
brain tumors are primary. The opposite is true in adults.
-
Benign vs. malignant:
Benign tumors are slow-growing, noncancerous, and do not spread
to surrounding tissue. Malignant tumors, on the other hand, are
cancerous. Fast-growing and aggressive, they can invade nearby
tissue and also are more likely to recur after treatment. Though
malignancies are generally associated with a worse outlook, in
the brain, benign tumors can be just as serious, especially if
they're in a critical location (such as the brain stem, which
controls breathing) or grow large enough to press on vital brain
structures.
-
Localized vs. invasive:
A localized tumor is confined to one area and is generally easier
to remove, as long as it's in an accessible part of the
brain. An invasive tumor has spread to surrounding areas and is
more difficult to remove completely.
-
Grade:
The grade of a tumor indicates how aggressive it is. Today, most
medical experts use a system designed by the World Health
Organization (WHO) to identify brain tumors and help make a
prognosis. The lower the grade, the less aggressive the tumor and
the greater the chance for a cure. The higher the grade, the more
aggressive the tumor and the harder it may be to cure.
What Causes a Brain Tumor?
Most brain tumors in children originate when a normal cell
begins to grow abnormally and reproduce too rapidly. Eventually
these cells develop into a mass called a tumor. The exact cause of
this abnormal growth is unknown, though research continues on
possible genetic and environmental causes.
Some kids are more susceptible to developing brain tumors due to
certain genetic conditions. Diseases such as
neurofibromatosis
, von Hippel-Lindau disease, Li-Fraumeni syndrome, and
retinoblastoma are all associated with a higher risk of brain
tumors.
Signs and Symptoms
A brain tumor can cause symptoms in a number of ways: by
directly destroying brain cells, by causing swelling at the tumor
site, by causing a buildup of fluid in the brain (hydrocephalus),
and by increasing pressure within the skull. A range of symptoms
can develop as a result.
Signs or symptoms vary depending on a child's age and
the location of the tumor, but may include:
- seizures
- weakness of the face, trunk, arms, or legs
- slurred speech
- difficulty standing or walking
- poor coordination
- headache
- in babies, a rapidly enlarging head
Because early warning signs can be gradual and may mimic those
of other common childhood conditions, brain tumors can be difficult
to diagnose. So it's always wise to discuss any symptoms that
concern you with your child's doctor.
Diagnosis
A doctor who suspects that a child has a brain tumor will order
imaging studies of the brain: a CT scan or MRI, possibly both.
These procedures let doctors see inside the brain and pinpoint the
area of the tumor. Although both are painless, they do require
children to be very still. Kids usually don't require sedation
for CT scans, which can be done fairly quickly.
Most, however, do need to be sedated for an MRI scan.
If imaging studies reveal a brain tumor, then surgery is likely to
be the next step. A pediatric neurosurgeon will try to remove the
tumor; if complete removal is not possible, then partial removal -
or at least a biopsy (removal of a sample for microscopic
examination) - may be done to confirm the diagnosis.
A pediatric pathologist (a doctor who helps diagnose diseases in
children by looking at body tissues and cells under a microscope)
and a neuropathologist (a pathologist who specializes in diseases
of the nervous system) then review the tissue to classify and grade
the tumor.
Special tests such as karyotyping, PCR, FISH, and gene
expression profiling might be used to analyze the genetic makeup of
the tumor cells. Using these tests to get specific information
about cancer cells helps doctors develop the best treatment plan
for someone with a brain tumor.
Treatment
Most pediatric brain tumor patients require treatment with some
combination of surgery,
radiation
therapy, and
chemotherapy
. Advancements in all three areas have contributed to better
outcomes over the last few decades.
The care of a child with a brain tumor is very complicated and
requires close coordination between many members of a medical team.
Members of this team typically include:
- a pediatric neuro-oncologist (a doctor who specializes in
treating cancers of the brain or spine)
- a pediatric neurologist (a doctor who specializes in
disorders of the nervous system)
- a pediatric neurosurgeon (a surgeon who operates on the brain
or spine)
- a radiation therapist (a specialist who administers radiation
therapy)
- rehabilitation medicine specialists, including speech,
physical, and occupational therapists
- psychologists and social workers
These experts must choose a child's therapy very carefully
because the potential for long-term effects, particularly from
radiation, is high. (Radiation therapy, though often effective, can
cause injury to the developing brain, especially in younger
patients.) Striking the delicate balance between giving just enough
therapy to cure the child, but not so much as to damage healthy
cells and cause unnecessary side effects, is probably the most
difficult aspect of treating brain tumors.
Surgery
Surgeons are having more success than ever removing brain
tumors, partly because of new technologies in the operating room -
especially those that allow real-time images of the brain to guide
surgeons as they operate. These include stereotactic devices, which
help target tumors by providing 3D images of the brain;
intraoperative MRI, which lets doctors see beyond what is exposed
during surgery and more clearly distinguish the boundary between
tumor and healthy tissue; and other image-guidance systems that
allow for more precise navigation.
Staged surgeries are also being used more frequently. That means
that instead of trying to remove a large tumor all at once,
surgeons will take a small part, and then attempt to shrink the
tumor with chemotherapy and/or radiation therapy. After several
months of treatment, the surgeon may go back a second or even a
third time to totally remove the rest of the tumor.
After surgery, some tumors may not require any more treatment
beyond observation (periodic checkups and imaging scans to watch
for trouble). Many, however, require more aggressive therapies,
such as radiation therapy, chemotherapy, or a combination of
both.
Radiation Therapy
Radiation therapy - the use of high-energy light to kill rapidly
dividing cells - is very effective in the treatment of many
pediatric brain tumors. However, because the developing brain in
children younger than 10 (and especially younger than 5) is highly
sensitive to its effects, radiation therapy can have serious
long-term consequences. These may include seizures, stroke,
developmental delays, learning problems, growth problems, and
hormone problems.
As with surgery, the delivery of radiation therapy has changed
significantly over the last decade. New computer-assisted
technologies have allowed doctors to construct 3D radiation fields
that accurately target tumor tissue, while avoiding critical brain
structures, such as the hearing centers. Still, the advantages and
disadvantages of using radiation therapy should always be discussed
with your doctor.
Chemotherapy
Chemotherapy is the use of drugs to kill cancer cells.
Chemotherapy is often administered through a special long-lasting
intravenous (IV) catheter called a central line, and may require
frequent hospital stays. Although chemotherapy has many short-term
side effects (fatigue, nausea, vomiting, hair loss, etc.), it has
fewer long-term side effects than radiation therapy. Many children
with brain tumors are treated with chemotherapy in order to delay
or avoid radiation treatment.
Unlike brain tumors in adults, many pediatric brain tumors are
highly sensitive to the effects of chemotherapy and respond well to
high doses of it. However, giving a child high-dose chemotherapy
can cause serious damage to the bone marrow (the spongy material
inside bones that produces blood cells).
To prevent bone marrow damage from becoming permanent, a
procedure called "stem-cell rescue" may be done. The
patient's own bone marrow or blood stem cells are collected and
stored until after the high-dose chemotherapy is completed. Then
the marrow or stem cells are infused back into the patient to help
the damaged bone marrow recover.
Common Types of Brain Tumors
There are many different types of pediatric brain tumors,
ranging from those that can be cured with minimal therapy to those
that cannot be cured even with aggressive therapy.
Some of the most common types are:
Astrocytomas
Astrocytomas come in four major subtypes: juvenile pilocytic
astrocytoma (grade 1), fibrillary astrocytoma (grade 2), anaplastic
astrocytoma (grade 3), and glioblastoma multiforme (grade 4). The
higher the grade, the more aggressive the tumor.
Another important feature of astrocytomas is location, because
where the tumor is directly affects the chance for a cure. For
example, astrocytomas in the cerebrum and cerebellum tend to be low
grade and located closer to the brain's surface, and so often
can be treated with surgery alone. Optic pathway gliomas (which
occur near the eyes) and astrocytomas (in the central parts of the
brain) cannot be easily removed and often require a longer, more
complex treatment approach.
Ependymomas
When located in the top part of the brain, these tumors often
can be cured by surgery alone. However, when located in the center
or back portion of the brain, they usually require much more
aggressive therapy and can be difficult to cure.
Brain Stem Gliomas
Diffuse pontine gliomas, the most common subtype of brain stem
gliomas, are located in a part of the brain that does not tolerate
surgery. Patients with brain stem gliomas typically are treated
with radiation therapy alone, although both surgery and
chemotherapy have been used, with little success. Long-term
survival rates are low for children with these tumors.
Medulloblastomas and Primitive Neuroectodermal Tumors
(PNETs)
These related tumors, which are identical under the microscope,
differ primarily in their location. Medulloblastomas are located in
the back part of the brain, near the brain stem, while PNETs can be
located anywhere else in the brain. Both tumors require aggressive
therapy, including surgery, chemotherapy, and radiation therapy.
Although these are dangerous cancers and the treatments are
intense, cure rates are improving every decade. In fact, the
majority of children with these types of tumors can now be
cured.
Craniopharyngiomas
These rare, benign tumors are slow-growing. Although they do not
spread, they can cause serious problems by putting pressure on
critical brain structures. Treatment typically involves surgery and
radiation, although in some cases surgery alone is used. Long-term
survival is excellent.
Germ Cell Tumors
These tumors usually arise from two special areas in the midline
of the brain, the area around the pituitary gland and the pineal
gland. They can be difficult to treat, but a cure is often possible
with aggressive surgery, radiation, and chemotherapy. Germinomas,
the most common type of germ cell tumor, can be treated with either
radiation therapy, chemotherapy, or both depending on the
circumstances.
Late Effects
"Late effects" are problems that patients can develop
after cancer treatments have ended. For survivors of pediatric
brain tumors, late effects may include cognitive delay, seizures,
growth abnormalities, hormone deficiencies, visual and auditory
problems, and the possibility of developing a second cancer,
including a second brain tumor. Because these problems sometimes
don't become apparent until years after treatment, careful
observation and regular screenings are needed to catch them as
early as possible.
In some cases, short-term effects may improve with the help of
physical, occupational, or speech therapy and may continue to
improve as the brain heals. In other cases, kids may experience
side effects that are longer term, including learning disabilities;
medical problems such as diabetes, growth delay, or delayed or
early puberty; physical disabilities related to movement, speech,
or swallowing; and emotional problems linked to the stresses of
diagnosis and treatment.
Be aware of the potential for physical and psychological late
effects, especially when the time comes for your child to return to
school, activities, and friendships. Talk to teachers about the
impact treatment has had on your child and discuss any
accommodations that may need to be made, including a limited
schedule, additional rest time or bathroom visits, modifications in
homework, testing or recess activities, and medication scheduling.
Your doctor can offer advice on how to make the transition
easier.
Caring for Your Child
Parents often struggle with how much to tell a child who is
diagnosed with a brain tumor. Though there's no
one-size-fits-all answer for this, experts do agree that it's
best to be honest - but to tailor the details to your child's
degree of understanding and emotional maturity.
Give as much information as your child requires, but not more.
And when explaining treatment, try to break it down into steps.
Addressing each part as it comes - visiting various doctors, having
a special machine take pictures of the brain, needing an operation
- can make the big picture less overwhelming.
Kids should be reassured that the brain tumor is not the result
of anything they did, and that it's OK to be angry or sad.
Really listen to your child's fears, and when you feel alone,
seek support. Your hospital's social workers can put you in
touch with other families of children with brain tumors who've
been there and may have insights to share.
Also be aware that it's common for siblings to feel
neglected, jealous, and angry when a child is seriously ill.
Explain as much as they can understand, and enlist family members,
teachers, and friends to help keep some sense of normalcy for them.
And finally, as hard as it may be, try to take care of yourself.
Parents who get the support they need are better able to support
their child.
Reviewed by:
Andrew W. Walter, MD
Date reviewed: June 2007
Note: All information is for educational purposes only. For specific medical advice,
diagnoses, and treatment, consult your doctor.
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